401 usually means a credentials issue.

I would suggest recording the page directly, rather than go through the HAR file as a proxy. Record with all headers. You likely have a missing credentials header on the fourth request.

As to removing the redirect, do you have a justification for altering in your script for a page load how the page load will work in production. Temporary redirects can be expensive on a collective basis, simply bypassing this load because it is inconvenient means that the load you are generating does not actually match the load in production, as you are loading the redirect target without the load of the redirect on the system (origin servers, network, client response, ....)